This game is made by Levarium Inc.
Levarium and Seaweedly are seen relaxing at they're house in Treetop City when Watermelloneers attack Treetop City. At this point King Horsetail summons the heroes to Treetop Castle and tells them to defeat 6 Watermelloneers. Once you do tell him and the first area Sky High City opens up.
More coming soon.